Conventionally, as devices for detecting relief patterns on the surfaces of objects, ones using prisms are known (refer to, for example, Patent Documents 1 and 2). A fingerprint pattern input device described in Patent Document 1 includes a triangular prism having at its upper surface a finger contact surface with which a finger is brought into contact, a light source disposed obliquely below the prism, for irradiating light toward the finger contact surface of the prism, and a camera for detecting a fingerprint image from reflected light reflected on the finger contact surface of the prism.
However, in the fingerprint pattern input device described above, because the finger contact surface of the prism is obliquely irradiated with light and reflected light thereof is also emitted in an oblique direction of the finger contact surface, a detected fingerprint image is of a fingerprint viewed obliquely, and there has been a problem that the image is distorted as compared to when viewed from the front. Therefore, devices using fiber optic plates in place of prisms in order to solve such problems are known (refer to, for example, Patent Documents 3 to 7).
A fingerprint detection device described in Patent Document 3 includes a fiber optic plate having an input end surface on which a finger is placed and an output end surface parallel to the input end surface, a light source disposed on the input end surface side, for irradiating light toward a finger, and a CCD camera disposed on the output end surface side, for imaging a fingerprint from light transmitted through the finger. In the fingerprint detection device, an image of a fingerprint viewed from the front can be obtained by imaging a fingerprint using light transmitted through a finger.